Scientists recently suggested that the Earth's sixth mass extinction has begun. As terrifying as that sounds, surely humans are too smart and too important to get wiped out? Palaeontologists have long tried to shed light ...

Around 252 million years ago, life on Earth collapsed in spectacular and unprecedented fashion, as more than 96 percent of marine species and 70 percent of land species disappeared in a geological instant. The so-called end-Permian ...

(Phys.org)—A pair of researchers with MIT has found a way to set a time line for volcanic activity in what is now Siberia, over 250 million years ago, and the worst mass extinction that ever occurred on our planet. In their ...

A pair of researchers, one with the University of Manchester, the other with the University of Salford, both in the U.K., has developed a new computer algorithm for estimating the body mass of extinct quadrupedal mammals. ...

Scientists at The Field Museum have identified a new species of pre-mammal in what is now Zambia. Thanks to a unique groove on the animal's upper jaw, it was dubbed Ichibengops (Itchy-BEN-gops), which combines the local Bemba ...

A computer science team at The University of Texas at Austin has found that robots evolve more quickly and efficiently after a virtual mass extinction modeled after real-life disasters such as the one that killed off the ...

Hawai'i has been called the "extinction capital of the world." But, with the exception of the islands' birds, there has until now been no accurate assessment of the true level of this catastrophic loss. Invertebrates (insects, ...

(Phys.org)—The Permian geologic period that ended the Paleozoic era climaxed around 252 million years ago with a sweeping global mass extinction event in which 90 to 95 percent of marine life became extinct. It would take ...

Extinction event

An extinction event (also known as: mass extinction; extinction-level event, ELE) is a sharp decrease in the number of species in a relatively short period of time. Mass extinctions affect most major taxonomic groups present at the time — birds, mammals, reptiles, amphibians, fish, invertebrates and other simpler life forms. They may be caused by one or both of:

Over 99% of species that ever lived are now extinct, but extinction occurs at an uneven rate. Based on the fossil record, the background rate of extinctions on Earth is about two to five taxonomic families of marine invertebrates and vertebrates every million years. Marine fossils are mostly used to measure extinction rates because they are more plentiful and cover a longer time span than fossils of land organisms.

Since life began on earth, several major mass extinctions have significantly exceeded the background extinction rate. The most recent, the Cretaceous–Tertiary extinction event, occurred 65 million years ago, and has attracted more attention than all others as it marks the extinction of nearly all dinosaur species, which were the dominant animal class of the period. In the past 540 million years there have been five major events when over 50% of animal species died. There probably were mass extinctions in the Archean and Proterozoic Eons, but before the Phanerozoic there were no animals with hard body parts to leave a significant fossil record.

Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty. These differences stem from the threshold chosen for describing an extinction event as "major", and the data chosen to measure past diversity.